Evaluating barley landraces collected in North Africa and the Middle East for powdery mildew infection at seedling and adult plant stages

AbstractBarley (Hordeum vulgare L.) is one of the most widely grown cereal crops. Numerous pathogens impair the amount and quality of the grain yield. Blumeria graminis f. sp. hordei (Bgh) is a fungal pathogen causing powdery mildew, a widespread and economically important foliar disease. Since there is a limited number of known resistance genes, efforts of scientists and breeders are focused on searching for new sources of resistance. Barley landraces are a known, but still underexploited source of diversity. A set of 79 barley landraces collected in North Africa and the Middle East was tested against powdery mildew at seedling and adult plant stages. Under a controlled environment, 50% of accessions showed resistance conditioned by major genes. Among them, seven accessions showed broad resistance to Bgh isolates that were virulent to most of the known resistance genes. The field experiments carried out under natural infection over several years indicated all accessions as potential sources for resistance breeding. Twelve landraces were found to be medium resistant or resistant during all six seasons. This report relates to barley landraces as a promising source of potentially novel resistance to powdery mildew.